Residents of bulging metropolises around the world should brace for an increase in stagnant, polluted air that hangs around for days as a result of climate change-related shifts in wind and rainfall patterns, according to a new study.

The findings highlight one way global warming can compromise human health …

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Poor air quality is related to a range of heart and lung complications that the World Health Organization estimates cause 3.7 million premature deaths a year.

“As we are doing pollution planning, we have to begin to make sure that we are including the climate change impacts,” said Nolen, who was not part of the new study but was asked to comment on its implications.

As Christoff notes, ‘this four-degree world is one of almost unimaginable social, economic and ecological consequences and catastrophes’ but, given current international and Australian energy and climate policies, it is “an impending reality”. The book contains contributions by Australia’s leading scientists and economists, including Ross Garnaut, David Karoly and Will Steffen, setting out a four-degree future across the ecological, social and economic impacts, and the adaptation that will be required.
Previously, climate change dialogue has mainly focused on two degrees Celsius of global temperature rise, which had been identified as a key environmental “tipping point”. Scientific consensus is now that our business-as-usual trajectory will cause the global average temperature to rise by a global average of four degrees Celsius above pre-industrial levels by 2070-2100.

Nonetheless, regional increases will range from four to sixteen degrees on land, with the Arctic continuing to heat up the most, as it has done to date.

One of the key insights from Four degrees or More? is that almost nothing about the consequences of climate change will be uniform.

Fish and aquatic life living in the high seas are more valuable as a carbon sink than as food and should be better protected, according to new research. The study found fish and aquatic life remove 1.5 billion tons of carbon dioxide from the atmosphere every year, a service valued at about $148 billion US. This dwarfs the $16 billion US paid for 10 million tons of fish caught on the high seas annually.

Record flooding in the Balkans has left least 20 people dead in Serbia and Bosnia and is forcing tens of thousands to flee their homes.

Meteorologists say the flooding is the worst since records began 120 years ago and is due to three months’ worth of rain falling on the region in three days. Goran Mihajlovic from Serbia’s Weather Centre said such rainfall happens once in 100 years.

In the eastern Bosnian town of Bijeljina, some 10,000 people were being evacuated on Saturday after the rain-swollen river Sava surged through flood defences.

Record May Heat, Drought, and Fires Scorch California

Record May heat sent temperatures soaring above 100° in much of Southern California on Wednesday, and fierce Santa Ana winds fanned fires that scorched at least 9,000 acres in San Diego County, forcing thousands to evacuate. Los Angeles Airport hit 96° on Wednesday, which is the hottest May temperature on record NOAA’s Threaded Extremes website (though apparently these records are not correct, since NWS Los Angeles says the all-time May record is 97°.) All-time May record heat was recorded at Camarillo (102°) and Oxnard (102°) on Wednesday. In Downtown Los Angeles, the mercury hit 99° on Wednesday, falling short of the all-time May record is 103° set on May 25, 1896. More record heat is forecast on Thursday, and hot offshore Santa Ana winds will bring extreme fire danger.

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Today’s U.S. Drought Monitor report showed grim news for California: 100% of the state is now in severe or higher drought, up from 96% the previous week. Though just 25% of California is classified as being in the highest level of drought, “Exceptional”, Erin McCarthy at the Wall Street Journal estimates that farms comprising 53% of California’s $44.7 billion market value lie in the Exceptional drought area.

Two teams of scientists say the long-feared collapse of the West Antarctic Ice Sheet has begun, kicking off what they say will be a centuries-long, “unstoppable” process that could raise sea levels by as much as 15 feet.

“There’s been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way,” Ian Joughin, a glaciologist at the University of Washington in Seattle, said in a news release about one of the studies published Monday. “This study provides a more qualitative idea of the rates at which the collapse could take place.”

The findings from Joughin and his colleagues, appearing in the journal Science, indicate that in some places, Antarctica’s Thwaites Glacier is losing tens of feet, or several meters, of ice elevation every year.

They estimate that Thwaites Glacier would probably disappear entirely in somewhere between 200 and 1,000 years. That loss would raise global sea levels by nearly 2 feet (60 centimeters). The glacier serves as a linchpin for the rest of the West Antarctic Ice sheet, which has enough frozen mass to cause another 10 to 13 feet (3 to 4 meters) of sea level rise.

As climate-change arguments continue at home — including pundits who assert the scientific consensus on the issue is overblown or concocted — current and former Department of Defense officials are mapping future strategies to protect U.S. interests in the aftermath of massive floods, water shortages and famines that are expected to hit and decimate unstable nations.

“For DoD, this is a mission reality, not a political debate,” said Mark Wright, a Pentagon spokesman. “The scientific forecast is for more Arctic ice melt, more sea-level rise, more intense storms, more flooding from storm surge, and more drought.

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But inside and outside the DoD, many experts agree U.S. national security already is being tested by massive unrest, revolts and humanitarian calamities triggered, in part, by climate change.

The civil war in Syria, which has left an estimated 100,000 people dead, has its roots in a regional drought, said retired Navy Vice Adm. Lee Gunn, now a member of the military advisory board for CNA Corporation, a non-profit research and analysis organization in Alexandria, Virginia.

TheNational Climate Assessmentis the definitive statement of current and future impacts of carbon pollution on the United States. And the picture it paints is stark: Inaction will devastate much of the arable land of the nation’s breadbasket — and ruin a livable climate for most Americans.

“Americans face choices” explains the Congressionally-mandated report by 300 leading climate scientists and experts, which was reviewed by the National Academy of Sciences. We’re already seeing serious climate impacts — such as more extreme heat waves, droughts, and deluges — and additional impacts are “now unavoidable.” But just how bad future climate change is “will still largely be determined by choices society makes about emissions.”

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One of the most dangerous consequences of that staggering rise in heat is a drop in soil moisture — basically precipitation minus evaporation — a key indicator of drought. Places that don’t see any drop in precipitation will still see a drop in soil moisture when it is hotter because of the evaporation, the drying out of the soil in the hot sun. Even worse is that much of the Southwest is projected to see less precipitation.

In a troubling new discovery, scientists studying ocean waters off California, Oregon and Washington have found the first evidence that increasing acidity in the ocean is dissolving the shells of a key species of tiny sea creature at the base of the food chain.

The animals, a type of free-floating marine snail known as pteropods, are an important food source for salmon, herring, mackerel and other fish in the Pacific Ocean. Those fish are eaten not only by millions of people every year, but also by a wide variety of other sea creatures, from whales to dolphins to sea lions.

If the trend continues, climate change scientists say, it will imperil the ocean environment.